Hashimoto Kazuhiko, Mega Keiko, Matsumoto Yuji, Bao Yanyuan, Yamano Yoshiaki, Morishima Isao
Department of Biochemistry and Biotechnology, Faculty of Agriculture, Tottori University, Japan.
Comp Biochem Physiol B Biochem Mol Biol. 2007 Nov;148(3):322-8. doi: 10.1016/j.cbpb.2007.06.011. Epub 2007 Jul 14.
Three cDNA clones encoding peptidoglycan recognition proteins (PGRP-B, -C and -D) were isolated from larval fat body of immunized Samia cynthia ricini. The deduced amino acid sequences show high homology to each other and also to Drosophila PGRP-LB, but rather lower homology to all of the known lepidopteran PGRPs including Samia PGRP-A, a receptor-type PGRP. The three PGRPs conserve the five amino acid residues which form the catalytic site of N-acetylmuramoyl L-alanine amidase as in Drosophila LB. The PGRP-C and -D genes were silent in naive larvae, but strongly induced in fat body by an injection of peptidoglycan. PGRP-B gene, in contrast, constitutively expressed at high levels in naive midgut, and the gene was weakly induced in fat body after injection of peptidoglycan.
从经免疫的蓖麻蚕幼虫脂肪体中分离出三个编码肽聚糖识别蛋白（PGRP-B、-C和-D）的cDNA克隆。推导的氨基酸序列彼此之间以及与果蝇PGRP-LB具有高度同源性，但与所有已知的鳞翅目PGRP（包括受体型PGRP——蓖麻蚕PGRP-A）的同源性较低。这三种PGRP保留了五个氨基酸残基，如同果蝇LB一样，这些残基构成了N-乙酰胞壁酰-L-丙氨酸酰胺酶的催化位点。PGRP-C和-D基因在未免疫的幼虫中不表达，但通过注射肽聚糖可在脂肪体中强烈诱导表达。相比之下，PGRP-B基因在未免疫的中肠中高水平组成性表达，注射肽聚糖后该基因在脂肪体中受到弱诱导。
